Media captionPresident Trump says North Korea will be in "big, big trouble" if it acts against Guam

China's President Xi Jinping has urged Donald Trump and North Korea to avoid "words and actions" that worsen tensions, state media say.

Mr Trump and North Korea have been exchanging hostile rhetoric, with the US president threatening to rain "fire and fury" on the North.

But China, North Korea's only major ally, has been urging restraint.

A White House statement said the US and China agreed North Korea must stop "provocative and escalatory behaviour".

A statement by North Korea's official KCNA news agency issued on Saturday said the Trump administration "had better talk and act properly," if it did not want "the American empire to meet its tragic doom".

Long-standing tensions over North Korea's nuclear programme worsened when it tested two intercontinental ballistic missiles in July.

The regime was also angered by last week's UN decision to increase economic sanctions against it.